A5015425497- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Advanced Chemical Physics Studies
- Phase Equilibria and Thermodynamics
- Superconducting and THz Device Technology
- Space Exploration and Technology
- Planetary Science and Exploration
- Radio Astronomy Observations and Technology
- Atomic and Molecular Physics
- Astrophysics and Cosmic Phenomena
- Advanced Combustion Engine Technologies
- Chemical Thermodynamics and Molecular Structure
- Calibration and Measurement Techniques
- High-pressure geophysics and materials
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
Leiden University
2015-2024
University of Amsterdam
2017-2024
Observatoire de Paris
2018-2021
The Netherlands Cancer Institute
2021
European Space Research and Technology Centre
2021
Radboud University Nijmegen
2021
University of California, Irvine
2021
Tartu Observatory
2020
Leiden Observatory
2003-2019
Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères
2018
We present the first high-resolution sub-mm survey of both dust and gas for a large population protoplanetary disks. Characterizing fundamental properties disks on statistical level is critical to understanding how evolve into diverse exoplanet population. use ALMA 89 around stars with $M_{\ast}>0.1~M_{\odot}$ in young (1--3~Myr), nearby (150--200~pc) Lupus complex. Our observations cover 890~$\mu$m continuum $^{13}$CO C$^{18}$O 3--2 lines. constrain $M_{\rm dust}$ few Martian masses...
Abstract We present Atacama Large Millimeter/Sub-Millimeter Array (ALMA) Band 6 observations of a complete sample protoplanetary disks in the young (∼1–3 Myr) Lupus star-forming region, covering 1.33 mm continuum and 12 CO, 13 C 18 O J = 2–1 lines. The spatial resolution is ∼0.″25 with medium 3 σ sensitivity 0.30 mJy, corresponding to M dust ∼ 0.2 ⊕ . apply Keplerian masking enhance signal-to-noise ratios our CO zero-moment maps, enabling measurements gas disk radii for 22 disks; we find...
Planets form in the disks around young stars. Their formation efficiency and composition are intimately linked to protoplanetary disk locations of "snow lines" abundant volatiles. We present chemical imaging CO snow line TW Hya, an analog solar nebula, using high spatial spectral resolution Atacama Large Millimeter/Submillimeter Array (ALMA) observations N2H+, a reactive ion large abundance only where is frozen out. The N2H+ emission distributed ring, with inner radius that matches model...
Icy bodies may have delivered the oceans to early Earth, yet little is known about water in ice-dominated regions of extra-solar planet-forming disks. The Heterodyne Instrument for Far-Infrared on-board Herschel Space Observatory has detected emission from both spin isomers cold vapor disk around young star TW Hydrae. This likely originates ice-coated solids near surface hinting at a ice reservoir equivalent several thousand Earth Oceans mass. water's ortho-to-para ratio falls well below...
We present a new code for solving the molecular and atomic excitation radiation transfer problem in gas predicting emergent spectra. This works arbitrary three dimensional geometry using unstructured Delaunay latices transport of photons. Various physical models can be used as input, ranging from analytical descriptions over tabulated to SPH simulations. To generate grid we sample input model randomly, but weigh probability with density other parameters, thereby obtain an average point...
The protoplanetary system HD 169142 is one of the few cases where a potential candidate protoplanet has been recently detected via direct imaging. To study interaction between and disk itself observations gas dust surface density structure are needed. This paper reports new ALMA continuum at 1.3\,mm, $^{12}$CO, $^{13}$CO C$^{18}$O $J=2-1$ emission from angular resolution $\sim 0".18 - 0".28$ ($\sim 20\,$au$ 33\,$au). reveals double-ring with an inner ring $0".17-0".28$ 20 35\,$au) outer...
Context. Water is a key tracer of dynamics and chemistry in low-mass star-forming regions, but spectrally resolved observations have so far been limited sensitivity angular resolution, only data from the brightest protostars published.
The key question about early protostellar evolution is how matter accreted from the large-scale molecular cloud, through circumstellar disk onto central star. A sample of 20 Class 0 and I protostars has been observed in continuum at (sub)millimeter wavelengths high angular resolution with Submillimeter Array. Using detailed dust radiative transfer models, we have developed a framework for disentangling emission envelopes disks, that estimated their masses. For sources sample, HCO+ 3-2 line...
We present ~2''-4'' aperture synthesis observations of the circumstellar disk surrounding nearby young star TW Hya in CO J = 2-1 and 3-2 lines associated dust continuum obtained with partially completed Submillimeter Array. The extent peak flux 230 345 GHz emission follow closely predictions irradiated accretion model Calvet et al. resolved molecular line extends to a radius at least 200 AU, full visible scattered light, shows clear pattern Keplerian rotation. Comparison images...
We present 0.3 arcsec resolution observations of the disk around GM Aurigae with Submillimeter Array (SMA) at a wavelength 860 um and Plateau de Bure Interferometer 1.3 mm. These probe distribution material on spatial scales commensurate size inner hole predicted by models spectral energy distribution. The data clearly indicate sharp decrease in millimeter optical depth center, consistent deficit distances less than ~20 AU from star. refine accretion model Calvet et al. (2005) based...
We present arcsecond-scale Submillimeter Array observations of the CO(3-2) line emission from disks around young stars HD 163296 and TW Hya at a spectral resolution 44 m/s. These probe below ~100 m/s turbulent linewidth inferred lower-resolution observations, allow us to place constraints on in disk atmospheres. reproduce observed using two physical models structure: (1) power-law temperature distribution with tapered density following simple functional form for an evolving accretion disk,...
In this paper, we present the first observations of Ophiuchus molecular cloud performed as part James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) with SCUBA-2 instrument.We demonstrate methods for combining these data previous HARP CO, Herschel, and IRAM N 2 H + in order to accurately quantify properties sources Ophiuchus.We produce a catalogue all found by SCUBA-2.We separate into protostars starless cores.We list cores perform full virial analysis, including external...
An unsolved problem in step-wise core-accretion planet formation is that rapid radial drift gas-rich protoplanetary disks should drive mm-/meter-sized particles inward to the central star before large bodies can form. One promising solution confine solids within small scale structures. Here we investigate dust structures (sub)mm continuum emission of four (TW Hya, HL Tau, HD 163296 and DM Tau), a sample with highest spatial resolution ALMA observations date. We retrieve surface brightness...
An era has started in which gas and dust can be observed independently protoplanetary disks, thanks to the recent surveys with ALMA. The first near-complete high-resolution disk survey both a single star-forming region been carried out Lupus, finding surprisingly low gas/dust ratios. goal of this work is fully exploit CO isotopologues observations comparing them physical-chemical model results, order obtain masses for large number disks. We have employed models analyze continuum Lupus...
The high spatial and line sensitivity of ALMA opens the possibility resolving emission from molecules in circumstellar disks. With an understanding physical conditions under which have abundance, they can be used as direct tracers distinct regions. In particular, DCO+ is expected to enhanced abundance within a few Kelvin CO freezeout temperature 19 K, making it useful probe cold disk midplane. We compare observations HD 163296 grid models. vary upper- lower-limit temperatures region present...
The composition of planetary solids and gases is largely rooted in the processing volatile elements protoplanetary disks. To shed light on key processes, we carry out a comparative analysis gas-phase carbon abundance two systems with similar age disk mass, but different central stars: HD 100546 TW Hya. We combine our recent detections C$^{0}$ these disks observations other reservoirs (CO, C$^{+}$, C$_{2}$H) gas mass warm tracers (HD, O$^{0}$), as well spatially resolved ALMA spectral energy...
The formation of planets strongly depends on the total amount as well spatial distribution solids in protoplanetary disks. Thanks to improvements resolution and sensitivity provided by ALMA, measurements surface density mm-sized grains are now possible large samples Such provide statistical constraints that can be used inform our understanding initial conditions planet formation. We analyze spatially resolved observations 36 disks Lupus star forming complex from ALMA survey at 890 micron,...
In recent years, the disk populations in a number of young star-forming regions have been surveyed with ALMA. Understanding properties and their correlation those central star is critical to understand planet formation. particular, decrease average measured dust mass age region has observed. We conducted high-sensitivity continuum ALMA observations 43 Class II stellar objects CrA at 1.3 mm (230 GHz). The typical spatial resolution 0.3". fluxes are used estimate masses disks, survival...
The physical and chemical conditions in Class 0/I protostars are fundamental unlocking the protostellar accretion process its impact on planet formation. aim is to determine which components traced by different molecules at sub-arcsecond scales (100 - 400 au). We use a suite of Atacama Large Millimeter/submillimeter Array (ALMA) datasets Band 6 (1 mm), 5 (1.8 mm) 3 (3 spatial resolutions 0.5 3" for 16 sources. envelope well C$^{18}$O, DCO$^+$ N$_2$D$^+$, with freeze-out CO governing...
Abstract Gas-rich circumstellar disks are the cradles of planet formation. As such, their evolution will strongly influence resulting population. In ESO DESTINYS large program, we study these within first 10 Myr development with near-infrared scattered-light imaging. Here present VLT/SPHERE polarimetric observations nearby class II system SU Aur in which resolve disk down to scales ∼7 au. addition new SPHERE observations, utilize VLT/NACO, HST/STIS, and ALMA archival data. The data show...